Originally Posted by
LondonElite
Actually, you probably don't. It is generally the case for countries that don't allow the voluntary acquisition of a second citizenship that such an act immediately removes your first citizenship. In other words, if you voluntarily acquired Canadian citizenship, your Country-A citizenship would have been revoked when this happened. That Country-A might not know about this yet, or that you still have the passport, doesn't matter.
You don't specify A, nor do you describe which citizenships you acquired how, but I think you might have a bigger problem on your hands than you suspect, and may have self-revoked your A citizenship.
Countries like the U.S. and Canada and such don't tell other governments about a person if he acquires citizenship from them and the home country doesn't usually know unless it's someone famous.